Method for preparing single crystal silicon and single crystal silicon

Abstract

The present invention discloses a method for preparing single crystal silicon and single crystal silicon. The method for preparing single crystal silicon comprises: obtaining the number N of times silicon material is put into a crucible; determining that N is greater than or equal to 2, and simultaneously putting dopants into a single crystal furnace while putting silicon material, wherein the dopants include antimony material and gallium material. The method for preparing single crystal silicon according to the present invention can improve the utilization rate of the crucible and the production efficiency of single crystal silicon, and can also increase the conductivity of single crystal silicon and improve the resistance uniformity of the crystal rod, thereby improving the quality of single crystal silicon.

Description

Technical Field

[0001] The invention relates to the technical field of single crystal silicon manufacturing, and in particular to a method for preparing single crystal silicon and the single crystal silicon. Background Art

[0002] In the related art, single crystal silicon is prepared by methods such as the Czochralski method, but the conductivity of the prepared single crystal silicon is limited, which affects the application of single crystal silicon in electronic devices, and the resistance uniformity of the crystal rod is difficult to control, which in turn affects the quality of the single crystal silicon. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing single crystal silicon, which can improve the utilization rate of the crucible and the production efficiency of single crystal silicon, and can also increase the conductivity of the single crystal silicon and improve the resistance uniformity of the crystal rod, thereby improving the quality of the single crystal silicon.

[0004] The present invention also provides a single crystal silicon, which is manufactured according to the above-mentioned single crystal silicon manufacturing method.

[0005] The method for preparing single crystal silicon according to an embodiment of the present invention includes: obtaining the number N of times silicon material is added into a crucible; determining that N is greater than or equal to 2, and adding dopants into the single crystal furnace while adding silicon material, wherein the dopants include antimony material and gallium material.

[0006] According to the method for preparing single crystal silicon of an embodiment of the present invention, when the number of times of adding silicon material into the crucible is greater than or equal to 2, dopants are added into the single crystal furnace at the same time as the silicon material, wherein the dopants include antimony material and gallium material. Adding materials in batches can increase the total amount of silicon material and dopants added into the crucible, and can also improve the doping efficiency, thereby improving the utilization rate of the crucible and the production efficiency of single crystal silicon. Antimony is an n-type Group V element that can provide free electrons, while gallium is a p-type Group III element that can provide holes. The two elements can compensate each other to form antimony and gallium counter-doping, thereby increasing the conductivity of single crystal silicon. It can also reduce the resistivity deviation of the head and tail of the crystal rod, improve the resistance uniformity of the crystal rod, and thus improve the quality and yield of the crystal rod.

[0007] According to some embodiments of the present invention, the step of simultaneously adding dopants to the single crystal furnace while adding silicon material includes: obtaining the total weight of the silicon material added to the single crystal furnace at one time; determining the weight of the antimony material added to the single crystal furnace at one time based on the total weight of the silicon material added at one time; and determining the weight of the gallium material added to the single crystal furnace at one time based on the total weight of the silicon material added at one time.

[0008] In some embodiments of the present invention, determining the weight of the antimony material added to the single crystal furnace at a time according to the total weight of the silicon material added at a time includes: the concentration of the antimony material in the silicon material is a, and satisfies: 11000ppbw≤a≤18000ppbw.

[0009] In some embodiments of the present invention, determining the weight of the gallium material added to the single crystal furnace at a time according to the total weight of the silicon material added at a time includes: the concentration of the gallium material in the silicon material is b, and satisfies: 100ppbw≤b≤1100ppbw.

[0010] In some embodiments of the present invention, the concentration of the antimony material in the silicon material is a, the concentration of the gallium material in the silicon material is b, and the ratio of a to b satisfies: 10:1-180:1.

[0011] According to some embodiments of the present invention, the gallium content concentration in the crystal rod obtained by the crystal pulling process is c, and satisfies: 0.8ppbw≤c≤35ppbw.

[0012] According to some embodiments of the present invention, the antimony material is high-purity antimony, and the gallium material is high-purity gallium.

[0013] According to some embodiments of the present invention, after silicon material is first added into the crucible and before the first added silicon material is melted, an inert gas is introduced into the single crystal furnace.

[0014] According to some embodiments of the present invention, the antimony material and the gallium material are granular solids.

[0015] According to some embodiments of the present invention, the crystal pulling process includes: melting the material, so that the silicon material, the antimony material and the gallium material are completely melted; seeding, so that the seed crystal is rotated and slowly descended and the seed crystal is immersed in the liquid silicon material, and then the seed crystal is gradually raised and leaves the liquid surface of the liquid silicon material to form the crystal rod; necking, so that the seed crystal is quickly pulled upward; shouldering, so that the speed of pulling the crystal rod upward is slowed down, so that the diameter of the newly crystallized crystal rod increases rapidly until it reaches a preset crystal rod diameter; isodiametric growth, controlling the crystal rod to grow isodiametrically to a preset length with the preset crystal rod diameter; finishing, increasing the speed of pulling the crystal rod upward, so that the diameter of the newly crystallized crystal rod gradually decreases until the crystal rod leaves the liquid surface of the liquid silicon material.

[0016] The single crystal silicon according to the embodiment of the present invention is manufactured according to the above-mentioned method for manufacturing single crystal silicon.

[0017] According to the single crystal silicon of the embodiment of the present invention, when the number of times of adding silicon material into the crucible is greater than or equal to 2, dopants are added into the single crystal furnace at the same time as the silicon material, wherein the dopants include antimony material and gallium material. The batch feeding can increase the total amount of silicon material and dopants put into the crucible, and can also improve the doping efficiency, thereby improving the utilization rate of the crucible and the production efficiency of single crystal silicon. Antimony is an n-type Group V element that can provide free electrons, while gallium is a p-type Group III element that can provide holes. The two elements can compensate each other to form antimony and gallium counter-doping, thereby increasing the conductivity of single crystal silicon. It can also reduce the resistivity deviation of the head and tail of the crystal rod, improve the resistance uniformity of the single crystal silicon, and further improve the quality and yield of the single crystal silicon.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 Schematic diagram of a logic diagram of a method for preparing single crystal silicon according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] Reference below Figure 1 A method for preparing single crystal silicon according to an embodiment of the present invention is described.

[0025] like Figure 1 As shown, the method for preparing single crystal silicon according to an embodiment of the present invention includes:

[0026] Obtain the number N of times silicon material is added into the crucible;

[0027] Determine that N is greater than or equal to 2, and add dopants into the single crystal furnace at the same time as silicon material, the dopants including antimony material and gallium material.

[0028] Specifically, at the initial stage of loading, high-purity polysilicon raw material or recycled silicon material is placed in the quartz crucible of the single crystal furnace. The silicon material is usually in block form, and there are large gaps between the multiple block silicon materials in the crucible. Therefore, the crucible is preheated first to melt the block silicon material in the crucible, and the gaps between the multiple block silicon materials disappear. After the silicon material becomes liquid, the upper surface drops, so that silicon material and dopants can continue to be added to the crucible, which can improve the quality of silicon material and dopants added to the crucible before crystal pulling, so that more single crystal silicon can be prepared after each feeding, thereby improving the utilization rate of the crucible and the production efficiency of single crystal silicon.

[0029] When it is determined that the number of times the silicon material is added to the crucible is greater than or equal to 2, the antimony material and the gallium material are added to the single crystal furnace at the same time as the silicon material, so that the dopant is added after sufficient silicon material is added, and the batch feeding can reduce the volatilization and loss of the dopant at high temperature, which is conducive to improving the doping efficiency. After the dopant is added to the crucible, the melting material is started and the heating is continued, and then the crystal pulling process is carried out by the Czochralski method to obtain a crystal rod, thereby producing a single crystal silicon.

[0030] The process of introducing impurities into single crystal silicon to change the atomic structure and electronic properties of single crystal silicon. Antimony and gallium as dopants can change the conductivity of single crystal silicon. Antimony is an n-type Group V element that can provide free electrons, while gallium is a p-type Group III element that can provide holes. The two elements can compensate each other. Antimony doping increases the number of free electrons, while gallium doping increases the number of holes, thereby forming antimony and gallium counter-doping, which can increase the conductivity of single crystal silicon. In addition, in the process of pulling the crystal rod, by adding antimony and gallium dopants simultaneously, it can be ensured that the dopants are evenly distributed in the silicon melt, thereby reducing the resistivity deviation at the head and tail of the crystal rod, and improving the resistance uniformity of the crystal rod, thereby improving the quality of the crystal rod and the qualified rate of finished products, thereby improving production efficiency and reducing production costs.

[0031] According to the method for preparing single crystal silicon of an embodiment of the present invention, when the number of times of adding silicon material into the crucible is greater than or equal to 2, dopants are added into the single crystal furnace at the same time as the silicon material, wherein the dopants include antimony material and gallium material. Adding materials in batches can increase the total amount of silicon material and dopants added into the crucible, and can also improve the doping efficiency, thereby improving the utilization rate of the crucible and the production efficiency of single crystal silicon. Antimony is an n-type Group V element that can provide free electrons, while gallium is a p-type Group III element that can provide holes. The two elements can compensate each other to form antimony and gallium counter-doping, thereby increasing the conductivity of single crystal silicon. It can also reduce the resistivity deviation of the head and tail of the crystal rod, improve the resistance uniformity of the crystal rod, and thus improve the quality and yield of the crystal rod.

[0032] In some embodiments of the present invention, adding dopants into the single crystal furnace while adding silicon material includes:

[0033] Obtaining the total weight of silicon material added into the single crystal furnace at one time;

[0034] The weight of the antimony material added to the single crystal furnace is determined based on the total weight of the silicon material added at a time;

[0035] The weight of the gallium material added to the single crystal furnace at one time is determined according to the total weight of the silicon material added at one time.

[0036] It is understandable that the content of doping elements determines the electrical properties of single crystal silicon, such as conductivity type and resistivity. Therefore, the ratio of silicon material and dopants directly affects the resistivity of single crystal silicon, and thus affects its electrical properties and application areas. The weight of antimony and gallium materials added to the single crystal furnace at a time can be determined based on the total weight of silicon material added at a time, which can control the proportion of dopants, help maintain the integrity of the crystal structure, and avoid crystal defects caused by improper doping. Controlling the ratio of silicon material and dopants by weight also facilitates precise control of the amount of dopants added.

[0037] In some embodiments of the present invention, determining the weight of the antimony material added to the single crystal furnace at a time according to the total weight of the silicon material added at a time includes:

[0038] The concentration of antimony material in silicon material is a, and satisfies: 11000ppbw≤a≤18000ppbw.

[0039] If the concentration of antimony in silicon is too high, antimony will react violently with silicon liquid, which may cause splashing and destroy the furnace atmosphere, thus affecting the crystal formation rate, resulting in low crystal yield and high production cost. Excessive concentration may also reduce the integrity of the crystal and affect the electrical properties of the crystal. If the concentration of the dopant antimony is too low, the resistivity of the grown single crystal silicon may not reach the required resistivity range, and the doping efficiency is not high. Therefore, it is necessary to control the concentration of antimony in silicon to 11000ppbw-18000ppbw, which can not only ensure the resistivity of single crystal silicon, but also avoid affecting the integrity and yield of the crystal.

[0040] In some embodiments of the present invention, determining the weight of the gallium material added to the single crystal furnace at a time according to the total weight of the silicon material added at a time includes:

[0041] The concentration of the gallium material in the silicon material is b, and satisfies: 100ppbw≤b≤1100ppbw.

[0042] If the concentration of gallium in silicon is too high, the quality of the crystal will decline, affecting the integrity and electrical properties of the crystal. The segregation coefficient of gallium in silicon is only 0.08. If the concentration of gallium is too high, the axial and radial doping of the pulled silicon rod will vary greatly during the gallium-doped single crystal silicon production, the resistance distribution will be uneven, and the uniformity of the produced silicon wafers will be poor. If the concentration of gallium in silicon is too low, the expected electrical performance and mechanical strength requirements cannot be achieved. Therefore, it is necessary to control the concentration of gallium in silicon to 100ppbw≤b≤1100ppbw, which can not only ensure the electrical performance and mechanical strength of single crystal silicon, but also avoid affecting the integrity and yield of the crystal.

[0043] In some embodiments of the present invention, the concentration of the antimony material in the silicon material is a, the concentration of the gallium material in the silicon material is b, and the ratio of a to b satisfies: 10:1-180:1.

[0044] The concentration of antimony in dopants is higher than that of gallium. Antimony has a higher solubility in silicon, which can achieve the purpose of heavy doping without causing the impurity elements to precipitate in the crystal and affect the crystal performance. At the same time, the segregation coefficient of antimony is smaller than that of gallium. During the crystal growth process, it is relatively easy for antimony to enter the crystal from the melt, so more antimony is needed to achieve effective doping. Due to the large evaporation coefficient of antimony, there may be more antimony volatilization losses during the doping process, so more antimony is needed to ensure the doping efficiency and the final resistivity control.

[0045] At the same time, the concentration ratio of antimony material and gallium material in silicon material cannot be too large. Gallium has a low segregation coefficient and is not easy to be doped into single crystal silicon, which can easily lead to a large difference in gallium content at the head and tail of the crystal rod, resulting in a large difference in resistivity. Although the segregation coefficient of antimony is close to that of gallium, if the ratio is too large, it may over-compensate, resulting in uneven resistivity distribution. If the doping ratio of antimony and gallium is too small, the expected electrical performance requirements may not be achieved. If the ratio of gallium and antimony is too small, the holes in the silicon crystal cannot be effectively compensated, resulting in too high a net doping concentration at the tail of the crystal rod, affecting crystal growth and resistivity uniformity. Therefore, controlling the concentration ratio of antimony and gallium in silicon material within the range of 10:1-180:1 can better ensure the reverse doping effect of mutual compensation between antimony and gallium, and can better ensure the resistivity uniformity and yield of single crystal silicon.

[0046] In some embodiments of the present invention, the gallium concentration in the crystal rod obtained by the crystal pulling process is c, and satisfies: 0.8ppbw≤c≤35ppbw. If the concentration of gallium in the crystal rod is too high, the quality of the crystal rod will be reduced, affecting the integrity and electrical properties of the crystal rod. The segregation coefficient of gallium in silicon is only 0.08. If the concentration of gallium is too high, it will cause large changes in the axial and radial doping of the pulled crystal rod during the gallium-doped single crystal silicon production, uneven resistance distribution, and poor uniformity of the produced crystal rod. If the concentration of gallium in the crystal rod is too low, the expected electrical properties and mechanical strength requirements of the crystal rod cannot be achieved. Therefore, it is necessary to control the concentration of gallium in the crystal rod to 0.8ppbw≤c≤35ppbw, which can not only ensure the electrical properties and mechanical strength of single crystal silicon, but also avoid affecting the integrity and yield of the crystal rod, and reduce the difficulty of implementation.

[0047] In some embodiments of the present invention, Figure 1 As shown, the antimony material is high-purity antimony and the gallium material is high-purity gallium. This can prevent other elements from being mixed into the single crystal furnace and causing other impurities to be mixed into the crystal rod, which can improve the purity and quality of single crystal silicon. It is also convenient to accurately control the amount of added dopants and the proportion of dopants, which is conducive to maintaining the integrity of the crystal structure and avoiding crystal defects caused by improper doping.

[0048] In some embodiments of the present invention, Figure 1As shown, after the silicon material is first added to the crucible and before the first silicon material is melted, an inert gas is introduced into the single crystal furnace. Silicon material reacts easily with oxygen at high temperatures, resulting in oxidation. Oxidation not only reduces the purity of single crystal silicon, but also introduces defects, seriously affecting its performance. Inert gases such as argon can isolate the air and prevent oxygen from entering the sub-chamber, thereby protecting the silicon material from oxidation. Inert gases such as argon can carry away volatile oxide impurities and other harmful substances during the flow process, which helps to keep the growth environment of single crystal silicon clean and pure. By controlling the atmosphere in the sub-chamber, defects such as voids and inclusions generated during the growth process of single crystal silicon can be reduced, which is beneficial to improving the performance and service life of single crystal silicon.

[0049] In some embodiments of the present invention, Figure 1 As shown, the antimony and gallium materials are solid granules, which are convenient for storage and feeding. The amount of antimony and gallium materials added to the single crystal furnace is determined according to the total weight of the added silicon material. The granular antimony and gallium materials are convenient for accurately controlling the amount of materials added to the single crystal furnace, thereby ensuring the integrity and yield of the crystal rod growth.

[0050] In some embodiments of the present invention, Figure 1 As shown, the crystal pulling process includes:

[0051] Melting materials to completely melt silicon, antimony and gallium;

[0052] Seeding, which makes the seed crystal rotate and slowly descend and immerse the seed crystal in the liquid silicon material, and then makes the seed crystal gradually rise and leave the liquid surface of the liquid silicon material to form a crystal rod;

[0053] Neck shrinkage, pull the seed crystal upward quickly;

[0054] The shoulder is released to slow down the speed of pulling the crystal rod upward, so that the diameter of the newly crystallized crystal rod increases rapidly until it reaches the preset crystal rod diameter;

[0055] Constant diameter growth, controlling the crystal rod to grow constant diameter to a preset length with a preset crystal rod diameter;

[0056] At the end, the speed of pulling the crystal rod upward is increased, so that the diameter of the newly crystallized crystal rod gradually decreases until the crystal rod leaves the surface of the liquid silicon material.

[0057] It is understandable that after the loading is completed, the crucible is placed in the graphite crucible in the single crystal furnace, and then the single crystal furnace is evacuated to maintain it within a certain pressure range, and then filled with a certain flow and pressure of protective gas, and finally heated to a temperature exceeding the melting point of the silicon material 1412°C to fully melt it. When the silicon crystal rod grows, the oriented seed crystal is first fixed on the rotating seed crystal rod, and then the seed crystal is slowly lowered, and paused for a moment 10mm away from the liquid silicon surface, so that the seed crystal temperature is as close to the molten silicon temperature as possible to reduce possible thermal shock. Then the seed crystal is gently immersed in the molten silicon, so that the head first dissolves a small amount, and then forms a solid-liquid interface with the molten silicon, and then the seed crystal gradually rises, and the temperature of the silicon connected to the seed crystal and leaving the solid-liquid interface decreases, forming a single crystal silicon, thereby completing the seeding stage.

[0058] After seeding is completed, the seed crystal is quickly pulled upward, the growth rate of the crystal rod is accelerated, and the diameter of the newly crystallized single crystal silicon will be smaller than the diameter of the seed crystal. The necking removes the dislocation-free seed crystal with surface mechanical damage. Seeding to the target length, slowing down the pulling speed of the crystal rod, lowering the temperature, and rapidly increasing the diameter. The shouldering process adjusts the shoulder shape by matching the diameter with the temperature. After the shoulder is released to the target diameter, it is necessary to quickly change the growth direction of the crystal rod from the horizontal to the vertical direction, increase the pulling speed, and the crystal rod stops growing horizontally. When the diameter no longer increases, the shouldering is completed.

[0059] When the shoulder reaches the predetermined crystal rod diameter, the growth rate of the crystal rod accelerates and maintains an almost fixed speed, so that the crystal rod maintains a fixed diameter growth. Equal diameter is the main part of the crystal rod growth, and the raw material of the single crystal silicon wafer can be obtained. If the single crystal silicon is directly separated from the liquid surface after the growth is completed, the thermal stress will produce a large number of dislocations at the interface, and extend upward by about a diameter, making the tail of the crystal rod unusable. Therefore, when the growth of the crystal rod is nearing the end, the growth rate is accelerated again, and the temperature of the silicon melt is increased at the same time, so that the diameter of the crystal rod continues to shrink, forming a cone, and finally the crystal rod leaves the liquid surface, the finishing stage ends, and the growth of single crystal silicon is completed.

[0060] The single crystal silicon according to the embodiment of the present invention is manufactured according to the above-mentioned method for manufacturing single crystal silicon.

[0061] According to the single crystal silicon of the embodiment of the present invention, when the number of times of adding silicon material into the crucible is greater than or equal to 2, dopants are added into the single crystal furnace at the same time as the silicon material, wherein the dopants include antimony material and gallium material. The batch feeding can increase the total amount of silicon material and dopants put into the crucible, and can also improve the doping efficiency, thereby improving the utilization rate of the crucible and the production efficiency of single crystal silicon. Antimony is an n-type Group V element that can provide free electrons, while gallium is a p-type Group III element that can provide holes. The two elements can compensate each other to form antimony and gallium counter-doping, thereby increasing the conductivity of single crystal silicon. It can also reduce the resistivity deviation of the head and tail of the crystal rod, improve the resistance uniformity of the single crystal silicon, and further improve the quality and yield of the single crystal silicon.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0063] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing single crystal silicon, characterized in that: include: Obtain the number N of times silicon material is added into the crucible; It is determined that N is greater than or equal to 2, and dopants are added into the single crystal furnace at the same time as silicon material, wherein the dopants include antimony material and gallium material.

2. The method for preparing single crystal silicon according to claim 1, characterized in that: The step of simultaneously adding dopants into the single crystal furnace and silicon material comprises: Obtaining the total weight of silicon material added into the single crystal furnace at a single time; Determining the weight of the antimony material added into the single crystal furnace at a time according to the total weight of the silicon material added at a time; The weight of the gallium material added into the single crystal furnace at a time is determined according to the total weight of the silicon material added at a time.

3. The method for preparing single crystal silicon according to claim 2, characterized in that: The step of determining the weight of the antimony material added to the single crystal furnace at a time according to the total weight of the silicon material added at a time comprises: The concentration of the antimony material in the silicon material is a, and satisfies: 11000ppbw≤a≤18000ppbw.

4. The method for preparing single crystal silicon according to claim 2, characterized in that: The determining the weight of the gallium material added into the single crystal furnace at a time according to the total weight of the silicon material added at a time comprises: The concentration of the gallium material in the silicon material is b, and satisfies: 100ppbw≤b≤1100ppbw.

5. The method for preparing single crystal silicon according to claim 2, characterized in that: The concentration of the antimony material in the silicon material is a, the concentration of the gallium material in the silicon material is b, and the ratio of a to b satisfies: 10:1-180:

1.

6. The method for preparing single crystal silicon according to claim 1, characterized in that: The gallium concentration in the crystal rod obtained by the crystal pulling process is c, and satisfies: 0.8ppbw≤c≤35ppbw.

7. The method for preparing single crystal silicon according to claim 1, characterized in that: The antimony material is high-purity antimony, and the gallium material is high-purity gallium.

8. The method for preparing single crystal silicon according to claim 1, characterized in that: After silicon material is first added into the crucible and before the first added silicon material is melted, inert gas begins to be introduced into the single crystal furnace.

9. The method for preparing single crystal silicon according to claim 1, characterized in that: The antimony material and the gallium material are granular solids.

10. The method for preparing single crystal silicon according to claim 1, characterized in that: The crystal pulling process includes: Melting material, so that the silicon material, the antimony material and the gallium material are completely melted; Seeding, which makes the seed crystal rotate and slowly descend and immerse the seed crystal in the liquid silicon material, and then makes the seed crystal gradually rise and leave the liquid surface of the liquid silicon material to form a crystal rod; Neck shrinking, and pulling the seed crystal upward rapidly; The shoulder is released to slow down the speed of pulling the crystal rod upward, so that the diameter of the newly crystallized crystal rod increases rapidly until it reaches a preset crystal rod diameter; Isometric growth, controlling the crystal rod to grow isometrically to a preset length with the preset crystal rod diameter; At the end, the speed of pulling the crystal rod upward is increased, so that the diameter of the newly crystallized crystal rod gradually decreases until the crystal rod leaves the liquid surface of the liquid silicon material.

11. A single crystal silicon, characterized in that: The method for preparing single crystal silicon according to any one of claims 1 to 10.

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